Why don't you make a dynamic-dispatch thermal chamber controller system? Make it so I you can drop it in existing programs, tell it what kind of controller it needs to talk to (or, better yet, have it figure that out by itself) and make it just work. That way, I you can move my your ATE to whatever thermal chamber is available without having to hard-code the commands for each controller type. Make it a plug-in architecture so we you don't have to upgrade the core software whenever we you extend the controller software. I'm thinking that Watlow F4, Cincinnati Sub-Zero and Thermotron (4800, 8800) would be a good place to start.
Post it here when you're done so we can see your work.